Possible Dumb Question about National “Special Reports”

Hello, all.

I’ve been fascinated with the news industry since I was a teenager. I’m not in the industry, but I saw a weird local flub during the Biden address that just happened that I wanted clarification on

Our local NBC affiliate went about their 6pm (8ET) newscast as if they didn’t know the address was happening and then mid-top story, the anchor hesitated and then threw it to the Biden address as if they were totally unprepared for it even though all major networks seemed to have the Addressed listed on their programming.

Is there an email/some sort of heads up, whether minutes or hours ahead of time that says “Hey, at 6pm, switch to the National feed” or when something is breaking nationally is there a heads up for the local affiliate before we see it on our end?

Who does that flub fall back on?

Sorry for what you all may think is like a 5th grader asking the question but I’m generally curious and respect the heck out of you all in the news industry.

“Curious” James